Method for disposal of waste picle liquor



Patented Dec. 5, 1950 METHOD FOR DISPOSAL F WASTE PICIKILE LIQUGR Samuel S. Heide, Birmingham, Ala, assignor to Tennessee Coal, Iron and Railroad Company, a corporation of Alabama No Drawing. Application April 7, 1948, Serial No. 19,650

a calm.

This invention relates to the disposal and utilization of steel-mill wastes and, in particular, tea method of disposing of waste pickle liquor and salvaging the solute.

The method of my invention may be carried out in almost any convenient manner. Since greater emciency may be obtained by processing materials in large quantities, I preferably employ Pickle liquor, a dilute solution of sulphuric a large refractory-lined container, run the liquor acid, is used in large volumes by the steel ini the container nd then clump molten slag dustry and the disposition of the spent liquor. i insttnce *8? a mixed solution of ferrous sulphate and acid, gg ig l ggg gg g f g s presents serious problem This prolmem is W m t; a d oth of aboiii l' frofn i313 c ars on a growing more pressmg because ofihresurictmns track along one side thereof to form a bottom agamst stream pollution now becom g common or lining. Several thousand gallons of waste which limit the disposition by natural drainage pickle liquor are then delivered to the it and of liquids inimical to utilization of natural waters molten b1ast fumace 81 2g is poured 5 the for industrial and municipal supplies. Several M liquor in an amount having a Weight about equal thod fo the disposal of Waste l q r have to or somewhat less than that of the liquor. The bgentproposgd but none of themohas a ig g liquor is at atmospheric temperature and on con- F OD as I am aware' sue me o tact therewith, the slag is granulated by the sudmvolves neutralization by milk of lime, limestone den cooling and the liquor disposed of by evapo or dolomite; another the conversion of remainso ration of the water and combination of the acid to ferrous sulphate and recovery of the solute with the lime or other basic material oflatter by concentration; and still another the the Slag. The granulated slag may be removed recovery of ferrous sulphate by crystallization from the pit by a grab bucket and dried for f the concentration 0f the remaining f crushing and screening preparatory to shipment. The Making, shaping and Treating steel The steam generated by the heat of the slag efp and Francis, 5th edition, p 1192)- A11 fectively agitates the mixture and assures subthese methods are costly because of the use stantially complete combination of the sulphate added neutralizing material and the necessity of radical of t liquor it t i of th slag, treating large V1u11eS of liquid the heat In another example of the practice of my inquired for evaporatmg the water content. vention, a larger amount of liquor, say several I have invented a novel method of i posing hundred thousand pounds of liquor, may readily of waste pickle liquor which is simple and inbe disposed of by dumping molten slag therein, expensive to carry out and results in a product as explained above. The ratio of the amount of of commercial value. Essentially, my method slag required is about .82 lb. of slag per pound of comprises bringing the liquor into contact with 5 liquor. A somewhat smaller ratio, say .75, may molten blast-furnace slag. The heat of the slag suflice if good distribution of the slag in the liquor evaporates the water of the liquor and the slag is obtained, 1. e., by moving the ladies back and becomes granulated by the resultant quick coolforth a substantial distance while pouring the ing. The ferrous salt and acid dissolved in the slag. In one instance, the liquor analysis was: liquor are decomposed and combine with a, part 40 water, 87.1%; free 25 4, 8 4, 8. of the calcium oxide or other basic material of Its specific gravity was 1.116 giving a weight of the slag, resultmg in a product of substantial 9.3 lb. per gallon. The analysis of the blastvalue as a fertilizer filler. Since the slag, like furnace slag was:

FeO SiO, M101 CaO MgO MnO S K10 Na 0 I .21 37.12 0.09 40.27 11.00 .40 1.10 1.04 .21

the liquor, is a waste product, this value is al- After granulation, the slag gave the following most clear gain, without counting the advantage analysis:

, 27 citric H1O FeO FeO lSiO A10 00 M0 M0 0s oso Tml 2 s 2 2 a 8 g n 8 8 4 K20 usable sgilzlgle Nazo obtained in the disposition of the waste liquor. Balance, H2O.

Material of this analysis is a highly desirable soil conditioner or fertilizer filler. For this purpose, it is an improvement over slag granulated in water as well as vegetable matter, such as peanut-hull bran or furfural residue. This is because the metallic compounds are rendered more readily available as plant food. The material may be readily crushed to the desired fineness. Its characteristics make it easy and harmless to handle. They also eliminate any difficulty in storage or distribution. The product is porous but non-hygroscopic, weighing about 62 pcf. When mixed (up to 20%) with fertilizer materials, such as super-phosphate, muriate of potash, ammonium sulphate or ammonium nitrate solution, it may be stored without lumping or caking, heating up, loss of ammonia or reversion of soluble P205. The presence of about of potash (K20) soluble in 2% citric acid is particularly advantageous.

Instead of dumping molten slag in a pool of liquor, I may discharge a stream of liquor against a stream of slag in the manner now practiced in granulating slag by contact with water. I may also provide a cooling tower or hood for condensing the vapor arising from the pit on contact of the molten slag with the liquor. I may also drain unconsumed liquor from the pit and recirculate it to a stream of entering slag to increase the efiiciency.

The invention has other advantages, of course, besides the value of the resulting by-product. The principal advantage, indeed, is that it makes possible the effective disposal of pickle liquor at practically no cost since the neutralizing agent, blast-furnace slag, is a waste material and, as tapped from the furnace, carries sumcient heat for evaporation and agitation of the liquor, thus eliminating the need for externally supplied heat or power. The water content of the liquor, after being evaporated, may be discharged into the air as steam or condensed and run off through natural drainage channels without causing pol lution. The basic ingredients of the slag serve to decompose the acid and salt dissolved in the liquor and neutralize the former. The product, as noted in the above analysis, has a substantial calcium sulphate content, 1. e., in the neighbor hood of 5%, while .the slag as tapped from the furnace has none.

Although I have disclosed herein but a preferred practice of my method, it will be evident that changes in the procedure described may be made without departing from the spirit of the invention or the scope of the. appended claims.

I claim:

1. In a method of disposin of waste pickle liquor comprising small amounts of sulphuric acid and ferrous sulphate in aqueous solution, the steps including bringing molten blastfurnace slag into contact with said liquor whereby the water of the liquor quenches and granulates the slag and is largely evaporated by the heat of the slag, and the basic components of the slag react with the solute of the liquor.

2. The method defined by claim 1 characterized by accumulating a pool of liquor and pouring the molten slag into the pool.

3. The method defined by claim 1 characterized by directing a stream of liquor into a stream of molten slag.

4. The method defined by claim 1 characterized by maintainin the ratio of slag to liquor at less than unity.

SAMUEL S. HEIDE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 238,240 Lippincott Mar. 1, 1881 1,310,382 Auld et a1 July 15, 1919 1,384,974 Shaw July 19, 1921 1,386,331 Heckman Aug. 2, 1921 1,428,633 Hoffman Sept. 12, 1922 FOREIGN PATENTS Number Country Date 363,550 Great. Britain Dec. 24, 1931 OTHER REFERENCES Hodge: Industrial and Engineering Chemistry, vol. 31, No. 11, Nov. 1939, pages 1364-1380. 

1. IN A METHOD OF DISPOSING OF WASTE PICKLE LIQUOR COMPRISING SMALL AMOUNTS OF SULPHURIC ACID AND FERROUS SULPHATE IN AQUEOUS SOLUTION THE STEPS INCLUDING BEINGING MOLTEN BLASTFURNACE SLAG INTO CONTACT WITH SAID LIQUOR WHEREBY THE WATER OF THE LIQUOR QUENCHES AND GRANULATES THE SLAG AND IS LARGELY EVAPORATED BY THE HEAT OF THE SLAG, AND THE BASIC COMPONENTS OF THE SLAG REACT WITH THE SOLUTE OF THE LIQUOR. 